Iti dau exemplu pentru prima hidrocarbura
100g CaHb.......92,3gC.......7,7gH
26g..................x......................y
x=24g...................n(niu)=24g/12g/mol=2molC=a
y=2g.....................n(niu)=2g/1g/molH= 2 molH=b
Hidrocarbura are formula bruta (CH)n si formula moleculara C2H2